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A-Basin's first downhill-only, mountain bike-only trail is now open!



"Atomic Janitor" is a one-mile descent that was completed in mid-September by trail crews from A-Basin and the International Mountain Bicycling Association's (IMBA) Trail Solutions program. It's a preview of what is to come over the next two summers, when trail crews will build out a new mountain biking and hiking singletrack network designed by IMBA master trail designer and former A-Basin employee, Joey Klein. 

The newly opened trail is only partially complete. Atomic Janitor will eventually allow riders to descend from Black Mountain Lodge at mid-mountain to the base area. In addition to Atomic Janitor, IMBA and A-Basin trail crews also built a new singletrack access route for the existing Argentine North Fork Trail, bypassing a short section of road and offering a more bike-friendly climbing option. 

"No other ski area in Colorado is doing what we're doing here [at A-Basin]. It's a blend of old-school traditional singletrack and that new breed of purpose-built enduro mountain biking. You're going to have to earn your turns to come up here and ride this stuff," - Joey Klein, IMBA Trail Solutions

Complete interview with Joey:


  • Length: 1 mile
  • Trail rating: Intermediate / blue
  • Access: Climb 1 mile up the summer road or the Argentine North Fork Trail
  • Cost: FREE!
  • Hiking allowed: No
  • E-Bikes allowed: No. A-Basin is on U.S. Forest Service land, which does not allow e-bikes on trails. 
  • Bike rentals on site: No
  • Bike haul on lifts: No


Construction will begin in summer 2020 on a large, cross-country-style mountain biking and hiking loop trail that will eventually create about a 10-mile ride option exploring much of the frontside of the mountain. The system could be described as backcountry--an old-school riding experience on bike-optimized trails. Most of the future trail network will also be open to foot traffic.

The future loop trail will ascend from mid-mountain to 12,500 feet at the top of the lift-served terrain, head west traversing the ridge line, descend into The Beavers area, and finish by crossing the top of the Pallavicini terrain before connecting to Atomic Janitor for the descent. There are currently no plans for lift-served riding, though A-Basin will be listening to rider demand. There are also no plans for a "bike park" with large jumps and built features, or for multiple bike-only descents. A-Basin currently intends to run the trails as a "cross-country" system.

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